According to a liquid crystal display apparatus, display is carried out by forming a thin liquid crystal layer by sealing a liquid crystal composition between a display side substrate and a liquid crystal drive side substrate facing with each other, and selectively changing the amount of the transmitted light or the reflected light of the display side substrate while electrically controlling the liquid crystal sequence in the liquid crystal layer by the liquid crystal drive side substrate.
Such a liquid crystal display apparatus has various driving systems such as the static drive system, the simple matrix system, and the active matrix system. Recently, as a flat display for a personal computer, a portable information terminal, or the like, a color liquid crystal display apparatus using a liquid crystal panel of the active matrix system or the simple matrix system has rapidly been spread.
FIG. 7 shows an example of a liquid crystal display apparatus panel of the active matrix system. The liquid crystal display apparatus 101 has the structure with a color filter 11 as the display side substrate and a TFT array substrate 12 as the liquid crystal drive side substrate facing with each other with a gap part 13 of about 1 to 10 μm provided therebetween, and the gap part 13 filled with a liquid crystal L and the circumference thereof sealed with a sealing material 14. The color filter 11 has the structure with a black matrix layer 16 formed in a predetermined pattern for shielding the light at the boundary part between the pixels, a pixel part 17 with a plurality of colors (in general, three primary colors of red (R), green (G) and blue (B)) arranged in a predetermined order for forming each pixel, an overcoat 18 and a transparent electrode 19 laminated in this order on the transparent substrate 15 from the side closer to the transparent substrate.
On the other hand, the TFT array substrate 12 has the structure with the TFT elements arranged on a transparent substrate and a transparent electrode provided (not shown). Moreover, an alignment layer 20 is provided on the inner surface side of the color filter 11 and the TFT array substrate 12 facing thereto. Then, by controlling the light transmittance of the liquid crystal layer on the rear side of the pixels colored in each color, a color image can be obtained.
Here, the thickness of the gap part 13, that is, the cell gap (the gap distance between the display side substrate and the liquid crystal drive side substrate) is the thickness of the liquid crystal layer itself. Thus, for preventing the display mura such as the color mura and the contrast mura for providing the favorable display performances such as the even display, the quick response, the high contrast ratio and the wide view angle to the color liquid crystal display apparatus, the cell gap needs to be kept constant and even.
As a method for keeping the cell gap, there is a method of scattering a large number of spherical or rod like particles 21 of a certain size, made of a glass, an alumina, a plastic, or the like in the gap part 13 as the spacer, attaching the color filter 11 and the TFT array substrate 12 and injecting a liquid crystal. According to the method, the cell gap is determined and kept to the size of the spacer.
However, according to the method of scattering the particles in the gap part as the spacer, there have been the problems of such as facilitating an eccentricity of the spacer distribution. As a method for solving these problems of the particle like spacers, as shown in FIG. 8, a columnar spacer 22 having a height corresponding to the cell gap is formed in a region on the inner surface side of the color filter 11 which coincides with the position where the black matrix layer 16 is formed (non display area). The columnar spacer 22 is formed by coating a photosetting resin onto a transparent substrate of a color filter by an even thickness and carrying out the pattern exposure of the obtained coating film by the photolithography to cure the film in the region where the black matrix layer is formed, that is, in the non display area.
The columnar spacer is required to have a characteristic to be deformed easily with respect to a minute load. This is due to the following reason. For example, when the liquid crystal is left at a low temperature, the all members comprising the liquid crystal display apparatus tend to be contracted. Since the liquid crystal material has the largest contraction percentage among the constituent members, it is contracted in the direction so as to reduce the gap between the transparent substrates. At the time, if the deformation of the columnar spacer cannot follow the reducing of the gap, a negative pressure is generated inside the liquid crystal display apparatus, and as a result, vacuum bubbles (low temperature bubbles) can easily be generated in the liquid crystal display apparatus.
Moreover, for example at the time of using the liquid crystal display apparatus, heat is applied to the liquid crystal display apparatus by the heat emitted form the back light. In this case, the all members comprising the liquid crystal display apparatus tend to be expanded. In this case also, since the liquid crystal material has the largest expansion rate among the constituent members, it is expanded in the direction so as to widen the gap between the transparent substrates. At the time, as the case mentioned above, if the deformation of the columnar spacer cannot follow the above-expansion speed of the gap, a pressure is generated inside the liquid crystal cell, and as a result, a void is generated between the transparent substrate and the liquid crystal layer. Thereby, the liquid crystal material leaks out of the void so that the overflowed liquid crystal material drops off from the liquid crystal cell by the gravity so as to generate the mura (gravity mura).
On the other hand, it is required that the displacement amount of the columnar space is small at the time when a strong force was applied thereon and then eliminated therefrom. The reason is that, for example, in the finger push test or the like, when the local load was applied on the liquid crystal cell and if the displacement amount is large after elimination of the load, poor display quality may be caused.
Here, since the two characteristics contradict with each other, it is difficult to form a columnar spacer having both of the above-mentioned characteristics. Thus, it is difficult to form a liquid crystal display apparatus having a large deformation with respect to a minute load and a small displacement amount against a strong force.
A prior art has not been found out concerning the present invention.